The Comparison between Energy Density of Blue and Red Light which Activation Silver Nanoparticles to Inhibition Candida albicans Biofilms

Photodynamic inactivation (PDI) is a technique to inhibit microbial biofilm growth through the toxicity of Reactive Oxygen Species (ROS) compounds. ROS can be attack membrane, lipids, DNA and nucleic acid then initiate cell necrosis. This study aims to analyze the potential of red and blue LEDs to activating silver nanoparticles (AgNPs) to produce significant amounts of ROS that are believed to be toxic and lethal to Candida albicans biofilm cells. The effectiveness of the treatment in this study was evaluated through cell viability represented by Optical Density values and malondialdehyde levels. There were 4 treatment groups used as samples, namely the control group, the photosensitizer group, the light group, and the combination group of light with photosensitizer. The duration of light exposure ranged from 2 to 10 min with a power of 100 MW. The biofilm staining done to detection some indicator as an impact of photodynamic against mortality and survive cell with 2 dyes are XTT assay as cell viability values and the Thiobarbituric Acid Reactive Substances assay for malondialdehyde levels. The results showed that photoinactivation of Candida albicans biofilm with the lowest viability occurred in the treatment group of the combination of blue light with AgNPs with an irradiation duration of 10 min, namely 0.076 ± 0.005 and the treatment group of the combination of red light with AgNPs with an irradiation duration of 10 min, namely 0.131 ± 0.021. The data resulted in an inactivation rate of 94.68 ± 0.55 % for blue light and 90.98 ± 0.02 % for red light. The malondialdehyde levels were 1.563 nmol/mL for blue light and 1.514 nmol/mL for red light. The comparison of blue light treatment with red light is based on penetration in the cell, where blue light has low penetration but high energy which gives more opportunities to produce ROS at the triplet level. The combination of blue LED spectrum with AgNPs is highly effective in inactivating the metabolic activity of pathogenic microbial cells.